Improvement in springs for tiltsng-chairs



H. HOWSON. Spring for Ti1ting-Ghar. No. 21,0,4779 Patented uw. 10,1878`jcf.

l maman l UNITED STATES PATEN FFICe HENRY HOWSON, OF PHILADELPHIA,PENNSYLVANIA, ASSIGNOR TO THE HALE di, KILBURN MANUFACTURING COMPANY, OESAME PLACE.

IMPROVEMENT IN SPRINGS FOR TILTING-CHAIRS.

Specification forming part of Letters Patent No. 210,779, dated DecemberI0, 1878; application filed August 15, 1878.

To all whom t may concern:

Be it known that I, HENRY HoWsoN, of Philadelphia, Pennsylvania, haveinvented a new and useful Improvement in Springs for Chairs, die., ofwhich the following is a specification The object ot' my invention is tocombine with a chair an economical device for permit.- ting the seat ofthe chair to be rocked, and this object I attain in the followingmanner, reference being` had to the accompanying drawings, in whicl1-Figure l is a front view, partly in section, of the sea-t and part ofthe stand of a chair with my improvement; Fig. 2, a side view of thesame; and Fig. 3, a modified form of tor sion-spring which may beadopted in carrying out my invention.

In Figs. 1 and 2, A represents the seat of a chair, and B the post, thelower portion of which has ascrew-thread adapted to aninternally-threaded socket of a stand, as in ordinary office-chairs.There are on the under side ot' the seat two project-ions or lugs, Z d',which, in the present instance, form a part of a plate, D, secured tothe said seat; and there are two similar projections or lugs, c c', on across-bar, E, secured to or `forming a part of the post .B or these lugsc e maybe secured to any suitable stand or support when a swivelseatcapable of vertical adjustmentis not required.

A torsion-spring, preferably a piece of wire rope, Gr, similar to thatreferred to in the Letters Patent No. 203,739, granted to the Hale &Kilburn Manufacturing Company, assignee or" Cheney Kilburn, May 14,1878, is passed through all fonrlugs, and is secured byapin or otherwiseto the lug d of the seat and the lu g e of the stand, the rope passingfreely through the lug e of the stand and the lug d of the seat.

The wire rope G, in addition to the duty which it performs as atorsion-spring, which permits the seat to be rocked, also serves as asupport for the seatand as a pivot-pin.

In carrying out my invention I am not restricted to the use of wire ropefor a torsionspring. The latter, for instance, may consist of a rod,Fig'. 3, rounded at and near the opposite ends, Where it passes throughthe lugs, and ilattened in the middle, Where it can yield under torsion.

I do not desire to claim the combination of a torsion-sprin g with theseat and stand of a chair, nor a torsion-spring which also serves topivot thc seat to the stand; but

I claim as my invention- The combination of a chair-seat having two lugsor projections, d d', and a stand having two lugs or projections, c e',with a torsion, spring, G, secured at one end to one lug, d.,

` of the seat and at the opposite end to the lug c ot the stand, andiittin g freely in the lngd ot the seat and in the lug e of thc stand,all

set forth.

In testimony whereof I have signed my name to this specification iu thepresence of two subscribing witnesses.

HENRY HOWSON.

Nit-n esses z HARRY A. CRAWFORD, HARRY SMITH.

